Funds are requested for the purchase of a tandem Finnigan TSQ 70 triple quadruple mass spectrometer and a Hewlett-Packard Model 1090 microbore HPLC pump. The equipment will be used to support twelve projects funded by NIH. There are two major themes: analysis of DNA adducts (6 NIH grants, 45% instrument usage) and analysis of complex/simple lipids (4 NIH grants and 1 NSF grant, 35% instrument usage). Minor themes are peptides (sequencing and analysis of modified peptides), organometallics, and coupling capillary electrophoresis to tandem mass spectrometry. Including and NSF-funded investigator (P. LeQuesne) not cited below, eight of the thirteen investigators are located at Northeastern University. DNA adducts are the consequence of exposure of DNA damaging chemical or physical agents, such as polyaromatic hydrocarbons or ionizing radiation. There is no need to determine the risks to humans from such exposure. Tandem mass spectrometry is needed both for qualitative and quantitative studies of DNA adducts, especially because of the trace amounts of these adducts. Complex lipids constitute a difficult area of chemical analysis. The proposed instrument will contribute to this area of research, partly drawing together local investigators having this common interest. Northeastern University, as the principal user of this equipment, agrees to subsidize this purchase with a contribution of $40,000 and additional funds of $25,000 annually for a period of three years towards its maintenance and operation. Efficient use of the system is ensured by the participation of an experienced principal investigator and assisting personnel who will administer and supervise its operation and maintenance.